Anonymous
Anonymous asked in Education & ReferenceHomework Help · 1 decade ago

Algebra 1 Help!?

I am in the 8th grade and I am taking Algebra 1 for High School Credit. I am having prblems with my math like this one ( its supposed to be X squared).

9x2 - 21x- 18

--------------

-9x2 + 81

I can get the bottom part but not the top part.

Can some one please Help Me!!!!

Update:

I am in the 8th grade and I am taking Algebra 1 for High School Credit. I am having prblems with my math like this one ( its supposed to be X squared).

9x2 - 21x- 18

--------------

-9x2 + 81

I can get the bottom part wich is

-9(X^2 - 9)

-9 (x - 3)(x + 3)

But i am trying to get the Top Part thats the part i dont get.

Can some one please Help Me!!!!

4 Answers

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  • 1 decade ago
    Favorite Answer

    For the numerator:

    Factor out a 3 to make it easier

    3 * ( 3x2 - 7x - 6)

    3 * ( 3x + 2 ) ( x - 3)

    For the denomenator

    -9 * (x + 3) (x - 3)

    putting it all together

    3x + 2

    ---------

    -3(x+3)

  • 1 decade ago

    9x^2 -21x - 18 = 0

    (3x -9)(3x+2)=0

    3x-9 = 0 3x+2 =0

    3x = 9 3x = -2

    x=3 x = -2/3

  • 1 decade ago

    the bottom comes to -9(x^2 -9) which equals -9(x+3)(x-3).

  • 1 decade ago

    Not really sure what your asking... could you be clearer? Are you trying to solve for x that is next to "21"?

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